Various hoses are generally used in engine compartments of automotive vehicles for cooling the engine and supplying heat to the interior of the car. These hoses include those intended for use with low pressurized fluids which necessitate the use of a clamp to prevent disconnection and to maintain a fluid tight seal during use. A generally ring-shaped metal hose clamp is conventionally used so that the hose is reliably clamped by the inherent spring force designed into the construction of the clamp. It has been found desirable to provide the hose clamp at the site of assembly in a preexpanded state to facilitate its application and to increase the efficiency of the hose assembly connection process.
The aforementioned hose clamps were designed as an improvement over hose clamps of the type known from Hashimoto, et al., U.S. Pat. No. 4,425,682. When installing a hose clamp of the type disclosed in Hashimoto, et al., the hose clamp is first gripped and spread with a spreading tool into an expanded state while being positioned onto a fluid connection piece or the end of the hose. During the entire installation, the hose clamp must be kept spread open by means of the spreading tool. When the hose end has been pushed onto the connection piece, the expanded hose clamp is moved to its intended position by means of the spreading tool, and the spreading tool is detached from the hose clamp. The hose clamp springs back towards its original non-expanded state so as to compress about the hose thereby clamping the hose onto the connection piece in a fluid tight connection.
The use of a hose clamp pursuant to Hashimoto, et al., suffers from a number of disadvantages. For example, the use of such a hose clamp requires that one hand be used for manipulating the hose clamp with the spreading tool and the other hand for manipulating the hose end itself. This, plus the fact that the hose clamp can only be manipulated with a spreading tool and by applying considerable spreading force thereto, results in various installation problems and the possibility of improper connection which could result in fluid leaks and the like.
To this end there is known improvements to the aforementioned hose clamps which are operative for maintaining their expanded state without continuous manipulation of a spreading tool. Hose clamps of this type are known from, for example, Kimura, et al., U.S. Pat. No. 5,414,905; Oetiker, U.S. Pat. No. 5,203,809; Kawashima, et al., U.S. Pat. No. 5,185,907; Takahashi, U.S. Pat. No. 4,996,749; Muhr, U.S. Pat. No. 4,930,192; Takahashi, et al., U.S. Pat. No. 4,930,191; Kato, et al., U.S. Pat. No. 4,858,279; and Muhr, U.S. Pat. No. 4,773,129.
By way of example, Kimura, et al. discloses a self-locking hose clamp formed from a clamp body comprising a leaf spring arranged in the form of an annular band. The ends of the clamp body are bent relative to the main portion of the band to serve as grip strips. An engagement claw extends from one of the grip strips so as to be engageable with the other of the grip strips to hold the clamp body in a spread-diameter state in which the ends of the clamp body are close to each other. The engagement claw includes a claw portion projecting in an axially direction with respect to the annular band and a guide extending obliquely to the axial direction. The guide is operative for guiding the grip strips axially to guide the engagement claw into engagement with the opposing grip strip when the grip strips are brought towards each other in a circumferential direction to maintain the hose clamp in a spread-diameter state.
One of the deficiencies of the hose clamp pursuant to Kimura, et al. is the possible slippage of the engagement claw from the opposing grip strip, and in particular, in a lateral direction. In this event, the hose clamp due to the stored energy can become a dangerous projectile. Another deficiency of Kimura, et al. is the notable absence of a positive stop member. In this regard, as the grip strip engages the guide at the end of the engagement claw, this allows the grip strips to be brought closer together thereby further expanding the annular band. As a consequence, there is the possibility of over expanding the hose clamp thereby inducing adverse mechanical stresses that can affect the integrity of the hose clamp during use. This deficiency has been overcome by constructing a hose clamp having a stop member as known from European Patent Application EP O713993.
The European application discloses a hose clamp formed from an annular band having a notch that enables the formation of a bent up tab to provide a stop member. Although the stop member is operative to prevent over expansion of the hose clamp, the construction by including a notch to form the tab results in a number of disadvantages. For example, the presence of the notch affects the integrity or mechanical strength of the annular band. Further, the formation of the tab requires an additional forming step of bending thereby adding additional tooling and manufacturing process operations. Still further, to the extent there is the desire to manufacture a hose clamp which does not include a self-locking feature, such as disclosed in the aforementioned Hashimoto, et al., the tooling requirements and change over time can adversely impact on the manufacturing efficiency and versatility.
The other aforementioned known hose clamps that provide a self-locking feature also suffer from disadvantages. For example, they may include complicated construction features that require advanced tooling resulting in further manufacturing costs, the use of separate removable locking elements and the like. In the case of a removable locking element, this construction is considered dangerous, as the locking element often becomes a projectile when removed due to the spring force created by the hose clamp. Thus, it can be appreciated that there is still the need for further improvements in hose clamps which provide a self-locking feature.